Mix 3 tablespoons cilantro and next 7 ingredients in small bowl to blend. Set aside. Pour enough water into large pot to reach depth of 1 inch. Add steamer rack or basket. Top with 9-inch-diameter glass pie dish. Bring water to boil. Place fish in pie dish. Pour cilantro sauce over. Sprinkle with salt and pepper. Cover pot; steam fish just until opaque in center, about 6 minutes for snapper and 8 minutes for halibut. Serve with sauce; garnish with 2 tablespoons cilantro. Using a small knife, peel away the thin, light-brown skin from the portion needed. Then rub the peeled ginger back and forth over the raised bumps of a small porcelain ginger grater (found at Asian markets). *Available in the Asian foods section of many supermarkets, at some specialty foods stores, and at Asian markets.